This invention relates to a toner cartridge used in an electrophotographic printer, such as a laser printer, an LED printer, a copying machine, or a facsimile apparatus.
An electrophotographic printer consumes toners to print characters, pictures, etc. on a paper or the like. Because the toners are expendable supplies, it is necessary to replenish new toners to continue a printing operation of the electrophotographic printer. However, the replenishing of the toners brings some problems. Therefore, a toner cartridge holding the toners is realized to make the replenishing easy. Such a toner cartridge is, for example, disclosed in a Japanese Unexamined Patent Publication No. Tokkaihei 6-130814.
A conventional toner cartridge has a body that provides a developing chamber for containing a developing machine and a toner chamber for holding toners. The body includes a side wall which partially defines the developing chamber. The side wall has a drawing opening which leads to the developing chamber. The developing chamber and the toner chamber are partitioned by a flat partition, which partially defines the drawing opening. The partition has a toner supplying opening to supply the toners from the toner chamber to the developing chamber. The toner supplying opening is sealed or closed with a sealing film at a side of the developing chamber when the toner cartridge is in an unused state. The sealing film has a ribbon shape comprising first and second parts that are continuous with each other. The first part has a first end at one end of the sealing film and the second part has a second end at the other end of the sealing film. The first part is pasted to the partition to close the toner supplying opening. The first part is easily peeled from the partition. In this state, the first end is located near the drawing opening. The sealing film is bent at the boundary area between the first part and the second part to lay the second part on the first part. The second end is located out of the body through the drawing opening. The sealing film must be peeled from the partition and removed from the developing chamber when the toner cartridge is used in the electrophotographic printer. This is carried out by drawing the second end.
If the second end is drawn, the first part is gradually peeled from the partition and the toner supplying opening opens from one side to the other side. In this event, the toners held by the toner chamber partially pour into the developing chamber and fall on the sealing film. At the same time, a bent section of the sealing film moves on the first part to the first end. Thus, the bent section gathers the fallen toners on the first part toward the first end. The gathered toners have nowhere to go and prevent the sealing film from completely passing through the drawing opening. As a result, the sealing film breaks in two and one of the broken sealing films remains in the developing chamber.